The present invention is directed to a cable having an outer jacket on which a layer is provided for reducing friction of the cable.
It is known from the German OS No. 29 24 495 to provide a glide or slide layer of fluoropolymer particles on the outside jacket of a cable. This is achieved in that the actual jacket layer is subjected to a sintering process wherein the already low frictional resistance provided by the fluoropolymers is additionally reduced in that outwardly situated small particles of a glide layer produce a structural effect comparable to loose clippings or gravel on a hard surface. However, a precondition for achieving the desirable properties is that the outside jacket of the cable must have a correct composition, i.e., it is a composition consisting of fluoropolymers. It is also necessary to execute the sintering by means of a separate operation and to thereby additionally improve the gliding properties based on the abrasion of extremely fine particles.
From the printed European patent application No. A2 00 51 922, it is known to extrude a second layer onto an outside jacket of a cable with this second layer consisting of a material which noticeably reduces the frictional losses relative to the original, that is, the inner jacket. An additional adhesive intermediate layer is necessary in order to connect the two outside jackets to one another. The outer layer normally consists of a polypropylene or of a hard polyethylene (MDPE, HDPE). However, with the application of a double outside jacket, difficulties will arise because of an undesirable increase in the overall diameter of the cable will occur due to the second or outer layer because this layer cannot be applied with an arbitrarily thin thickness in the extrusion process.